Principles of Electrophysiology

Principles of Electrophysiology

1 Electrocardiogram (ECG) was developed by ?
A. Hewlet
B. Judkin
C. Einthoven
D. White


2 Sinoatrial (SA) node is located at the junction of ?
A. Right atrium and superior vena cava
B. Right atrium and inferior vena cava
C. Right atrium and left atrium
D. Right atrium and coronary sinus


3 PR interval of ECG represents time needed for activation of ?
A. Both atria
B. Atrioventricular node (AVN)
C. Both atria + Atrioventricular node (AVN)
D. Both atria + AVN + His Purkinje system


4 Which of the following statements is false ?
A. Body surface ECG is the timed sum of cellular action potentials in atria & ventricles
B. Repolarization occurs first on endocardium then proceeds to epicardium
C. Activation of atria & AV node is PR interval
D. QT interval is duration of activation & recovery of ventricles


5 Duration of action potential in cardiac myocytes is ?
A. 20 - 40 ms
B. 80 - 1600 ms
C. 200 - 400 ms
D. 500 - 800 ms


6 Which of the following participate in the cardiac myocyte action potential ?
A. Ion channels
B. Pumps, transporters
C. Exchangers
D. All of the above


7 Diastole corresponds to which phase of action potentials ?
A. Phase 1
B. Phase 2
C. Phase 3
D. Phase 4


8 Sodium-calcium exchanger transports how many Na+ for one Ca2+ ?
A. 1
B. 2
C. 3
D. 4


9 Automaticity is a property of ?
A. Sinoatrial (SA) node
B. His-Purkinje system
C. Coronary sinus
D. All of the above


10 Early after depolarizations occur during ?
A. Phases 0 and 1 of the action potential
B. Phases 1 and 2 of the action potential
C. Phases 2 and 3 of the action potential
D. Phases 3 and 4 of the action potential


11 Delayed after depolarizations occur after completion of ?
A. Phase 1 of action potential
B. Phase 2 of action potential
C. Phase 3 of action potential
D. Phase 4 of action potential


12 Cellular feature common to induction of DADs is the presence of ?
A. Increased Ca2+ load in the cytosol
B. Increased Na+ load in the cytosol
C. Increased K+ load in the cytosol
D. Increased Mg2+ load in the cytosol


13 Which of the following enhance Ca2+ loading sufficiently to produce DADs ?
A. Digitalis glycoside toxicity
B. Catecholamines
C. Myocardial ischemia
D. All of the above